(19)

(11)

EP 0 426 731 A1

(12)

(43) Date of publication: 15.05.1991 Bulletin 1991/20 (21) Application number: 89908683.0 (22) Date of filing: 25.07.1989

(51) International Patent Classification (IPC):  C22B 1/ 16( . ) C22B 1/ 242( . ) C01G 23/ 02( . ) C22B 34/ 12( . ) (86) International application number: PCT/AU1989/000315 (87) International publication number: WO 1990/001073 (08.02.1990 Gazette 1990/04)

(84) Designated Contracting States: AT BE CH DE FR GB IT LI LU NL SE (30) Priority: 26.07.1988 AU 19870000094 (71) Applicant: COMMONWEALTH SCIENTIFIC AND INDUSTRIAL RESEARCH ORGANISATION Parkville, VIC 3052 (AU)	(72) Inventors: HALL, John, Sydney Clayton, VIC 3168 (AU) CAREY, Ken, George Clayton, VIC 3168 (AU) HOLLITT, Michael, John 15 Bank Street South Melbourne, VIC 3205 (AU) (74) Representative: Stuart, Ian Alexander, et al  MEWBURN ELLIS York House 23 Kingsway London WC2B 6HP London WC2B 6HP (GB)